Has Dianne Feinstein outlived her moment? The five-term Democratic senator from California, who is also, at 84, the Senate’s oldest member, provoked a flood of such speculation when she announced on Monday that she had decided to run yet again for re-election. Democrats have moved left, pundits noted; California has moved left; and California Democrats have moved more to the left than Democrats anyplace else. Surely, some said, Feinstein’s time had come and gone.

Well, not exactly. Feinstein hasn’t outlived her moment because her moment—her time in sync with her fellow California Democrats—never actually existed. In her 25 years in the Senate, she has always stood well to the right of the Golden State’s other elected Democrats, not to mention its Democratic voters.

Indeed, Feinstein designed her initial appearance on the stage of statewide politics with the specific intent of showing just how far to the right of Democratic activists she actually stood. During her first bid for statewide office (she previously had served as San Francisco’s mayor), she delivered a speech to the delegates at the 1990 convention of the state’s Democratic Party in which she made damn clear that unlike John Van de Kamp—the state’s liberal attorney general, who was her opponent in that year’s Democratic primary for governor—she emphatically supported the death penalty.

Her ringing endorsement of San Quentin’s gas chamber produced an immediate and noisy chorus of boos from the delegates, as her campaign had anticipated and planned for, since her subsequent television commercials featured the footage of her standing at the podium, defying the fuzzy-headed liberal boo-birds and that wuss Van de Kamp while standing up for crime victims. Feinstein went on to lose November’s gubernatorial run-off to Republican Pete Wilson, but two years later she won election to the Senate.

The California of the early 1990s, when her senatorial career began, was a state in transition. The recession at the beginning of that decade hit California perhaps harder than any other state, since it was compounded by the concurrent end of the Cold War, which decimated the state’s largest industry and the anchor of its middle class—defense and aerospace manufacturing. Unable to find comparable employment, hundreds of thousands of engineers and production workers, disproportionately white and conservative (or at minimum, hawkish) left the state, even as millions of immigrants fleeing Mexico’s dysfunctional economy or Central America’s endemic violence arrived. In time, these and other demographic transformations moved the state well to the left.

But that leftward shift was already underway in the early 1990s, rendering Feinstein’s obeisance to the dogmas of economic orthodoxy and militarist adventurism electorally unnecessary. Beginning in 1992, the state has consistently voted for the Democrat in presidential elections, and has sent first Barbara Boxer and then Kamala Harris—two Democrats well to Feinstein’s left—to join her in the Senate.

Over the years, Feinstein has been a reliable Democratic vote on most occasions, but her persistent right turns on a number of landmark votes have marked her as the most conservative Democratic senator from a solidly blue state.

In 1999, Feinstein voted for the Gramm-Leach-Bliley bill, which tore down Glass-Steagall’s wall between depositor and investment banking. Most Democrats, to be sure, joined her, but Boxer—along with Russ Feingold, Tom Harkin, Barbara Mikulski, and Paul Wellstone, among others—voted no.

In 2000, Feinstein voted for the bill establishing “permanent normal trade relations”—free trade—with China. Almost immediately, American manufacturers began their exodus from the industrial Midwest to the low-wage, union-free Middle Kingdom.

In 2001, Feinstein was one of just 12 Democrats to vote for George W. Bush’s tax cuts to the wealthiest Americans, nine of whom came from states Bush had carried the previous November. No senator from a state that had voted as heavily against Bush as California chose to join her in support of the legislation. At the time of the vote, Feinstein was (and still is) among the wealthiest members of the Senate, with an estimated net worth in the hundreds of millions, thanks to the fortune amassed by her husband, Richard Blum.

In 2002, Feinstein voted for the resolution authorizing the United States to go to war in Iraq: 23 of her Democratic Senate colleagues, including Boxer, voted against the resolution, as did 24 of the California Democrats in the House—a clear majority of the state’s Democratic delegation. Indeed, on a host of issues, not just Boxer but the state’s leading House members, beginning with Nancy Pelosi and Henry Waxman, stood well to Feinstein’s left.

To be sure, Feinstein has been a stalwart defender of women’s rights, civil rights, and the environment, and a leading advocate of greater gun control. She has never embraced the role of heretic in the manner of Connecticut’s Joe Lieberman. At the same time, however, she has persistently vexed civil libertarians by her support for expanding the federal government’s right to conduct surveillance on American citizens without approval from FISA courts, and by her sponsorship of a constitutional amendment criminalizing desecration of the flag.

A number of these votes—most especially, her support for the invasion of Iraq and for the Bush tax cut—outraged her fellow California Democrats. Nonetheless, she has never faced any serious primary opposition, for a multitude of reasons. Initially, she and Boxer formed a kind of balanced Senate ticket for a state in transition to liberalism (to which Boxer pointed the way) but not all the way there yet (for which Feinstein brought up the rear).

Then, as state Republicans moved to the right, the imperative of defeating their nominees eclipsed any impulse to seek a more liberal alternative to Feinstein. After a time, she just became part of the state’s political landscape—a fixture that, theoretically, could be replaced, but there were always too many other electoral fights to be fought to make a challenge to Feinstein worth the effort.

This year, however, is different, chiefly for two reasons. First, by the metrics of election results, polling, and legislative output, California has clearly become the nation’s most liberal and most Democratic state. Hillary Clinton’s margin over Donald Trump in California was fully four million votes. Since the somewhat un-Republican Republican Arnold Schwarzenegger was re-elected governor in 2006, Democrats have won all 27 contests for statewide offices.

Moreover, since the state shifted to its “jungle primary” in 2012—under which only the top two finishers in the primary election, regardless of their party affiliation, move on to the general election ballot—a growing number of statewide November run-offs pit Democrat against Democrat. The top two finishers in the 2016 senatorial primary were two Democrats—Attorney General Kamala Harris and Representative Loretta Sanchez—which meant there was no Republican alternative on the November ballot.

As the 2018 election draws nigh, no serious Republican has come forth to run for governor or senator, and none is likely to. For the first time in Feinstein’s senatorial tenure, then, any serious opposition to her re-election, if opposition there be, can only come from her left.

The other reason this year may produce a primary opponent is Feinstein’s age. Should she win re-election and serve out her next term, she’ll be 91 and a half when it ends. This scenario would bring her in right under the actuarial wire, since the Social Security Administration projects that an 84-year-old American female is likely to live until 92.

Today’s Democrats are no strangers to having party elders lead the way, but some of them are still rendering extraordinary service: Bernie Sanders brought about a rebirth of the American left; Nancy Pelosi remains the most effective national legislative leader of the past hundred years. Feinstein can claim no such distinction. Besides, there’s no indication that either Sanders or Pelosi is planning an electoral future that would keep them in office until their 90s. Pelosi would have to serve seven more two-year terms in the House before reaching the age that Feinstein would be at the end of her next senatorial term.

The most likely figure to emerge as a Democratic challenger to Feinstein is State Senate President Kevin de Leon. To his fellow progressives, he should also be the most deserving, and to his fellow Californians, quite probably the candidate with the most compelling story. The son of Guatemalan immigrant parents (his father is also half-Chinese), de Leon was raised by his housekeeper mother, became a teacher, and in 1994 helped organize the massive Latino immigrant demonstration in opposition to the anti-immigrant Proposition 187. One of a number of young activists who worked under the tutelage of Miguel Contreras, the brilliant Los Angeles labor leader, de Leon was elected to the state Assembly from a racially diverse, heavily immigrant downtown Los Angeles district in 2006, and to the state Senate in 2010.

As Senate president, de Leon authored and steered to passage the landmark legislation that requires California to generate half its electricity from renewable sources by 2030. He also convinced his Senate colleagues to pass somewhat skeletal and provisional single-payer legislation, and conceived and persuaded the legislature to enact a pioneering bill to provide IRAs to the nearly seven million low-wage California workers who aren’t offered retirement benefits on the job, creating a state-managed fund through paycheck deductions from which workers would have to opt out.

Progressive retirement security scholars like Teresa Ghilarducci had been advocating for this type of legislation for years; de Leon’s was the first such endeavor to become law. To make the new law operational, however, he had to persuade the Obama administration to amend some Labor Department ERISA regulations. Once he did, seven other states passed copycat versions of the California law—which, unfortunately, Trump’s Labor Department has neutered by reinstating the original ERISA rules.

During Obama’s second term, de Leon emerged the state’s leading advocate for its massive immigrant community, steering to passage bills that doubled funding for legal services for undocumented residents and prohibiting some types of police cooperation with federal immigration authorities. On the morning after Donald Trump’s election, the state senate president released a defiant statement proclaiming that California would remain a welcoming home for immigrants, climate sanity, and human rights: He is the author of the newly enacted law designating California as a sanctuary state and prohibiting police from detaining immigrants on the basis of their legal status.

Though term-limited out of the state Senate next year, de Leon had not seriously planned to run for another office, as it looked likely he’d be a high-level environmental appointee in Hillary Clinton’s administration. While Trump’s election ended that possibility, it also created the circumstances under which de Leon has emerged as the state’s outstanding progressive leader.

Since it was by no means clear that Feinstein would seek re-election, he began considering a Senate race. So when Feinstein stunned San Francisco’s Commonwealth Club in late August by asserting that Trump could “be a good president” if he grew on the job, de Leon criticized her not just for her deficiency of realism but for her normalization of evil.

Other elected Democrats who might have entered the Senate race had Feinstein opted out, including Los Angeles Mayor Eric Garcetti, Secretary of State Alex Padilla, and Representative Adam Schiff, have all flocked to her standard since her Monday announcement. But two wealthy investors who’ve provided substantial funding and guidance to progressive causes, San Francisco’s Tom Steyer and Orange County’s Joe Sanberg, are said to be considering possible challenges to Feinstein.

Feinstein supporters’ main argument against the very idea of a Democratic challenge is that it would require a massive diversion of money and energy that should instead be invested in efforts to unseat Republicans. That’s an argument that cannot be easily dismissed: A challenge to Feinstein would indeed require millions of progressive dollars that could otherwise be spent on Democrat-versus-Republican races, just as efforts to beat back that challenge would also require the re-routing of Democratic dollars.

The counter to that criticism is that a de Leon candidacy holds promise of activating all wings of the new progressive California and bringing voters to the polls who wouldn’t otherwise turn out. Seven of the state’s 14 Republican members of Congress represent districts that Clinton carried last November; Democrats are contesting all of those districts. A high-profile candidacy by de Leon—who’s relatively young (50), progressive, Latino, and Asian—could bring enough Latino and young voters to the polls to help swing a number of those districts. For all their considerable merits, the same can’t be said of Steyer and Sanberg.

California has emerged as the capital of anti-Trump America, and, more than that, as the progressive model for America’s future. That shift is due as much to de Leon as to anyone else—even including Jerry Brown, the governor whom he prods from the left.